[A novel method of ovarian stimulation for in vitro fertilization (bromocriptine-rebound method) increases developmental potential of oocytes and pregnancy rate].

A novel method of ovarian stimulation for IVF is reported. Endocrine-normal ovulatory women with a history of unsuccessful IVF attempts by means of a long protocol of a GnRH agonist/hMG regimen (L regimen) were studied. Ovaries were stimulated by the three regimens described below. The bromocriptine-rebound (BR) regimen consisted of bromocriptine (B) 2.5mg/day administered daily beginning on day 4 of the preceding cycle and buserelin acetate administered beginning in early high phase. Administration of B was discontinued in the low phase of the IVF cycle and daily administration of hMG was begun 7 days later. HCG was administered when dominant follicles reached 16-18 mm in diameter. The bromocriptine-continuous (BC) regimen was the same as the BR regimen, except that B was administered until the administration of hCG. The L regimen was the same as the BR regimen, except that no B was administered. The pregnancy rate per oocyte retrieval was significantly higher on the BR regimen (56% in 70 cycles) than the L regimen (33% in 46 cycles), and lowest on the BC regimen (29% in 7 cycles). The rate of fertilization and cleavage per oocyte and the proportion of morphologically-good embryos were significantly higher on the BR regimen (59.1% and 57.3%, respectively) than the L regimen (46.3% and 48.0%, respectively), and lowest on the BC regimen (49.0% and 41.7%, respectively). Serum PRL concentrations (ng/ml) at the time hMG was started were 14.9 +/- 1.5, 7.9 +/- 1.7 and 2.5 +/- 0.7 on the BR, L and BC regimens, respectively. The results of this study show that the BR regimen increases the developmental potential of oocytes and the pregnancy rate, probably because of increasing serum PRL levels to within the normal range.